1. Field of the Invention
The present invention relates to an improved piercing nozzle for pouch fitments, which are used to control the removal of the contents of filled thermoplastic polymeric film pouches, particularly pouches which contain about 500 ml or more.
2. Description of Related Art
As is known, the use of plastic pouches is common with respect to packaging certain liquids and other fluid materials, e.g. milk, fruit juices, relish and the like. For example, milk has been sold in pouches from 250 ml up to about 1.9 liters. The plastic pouches are often made of polyethylene film. In order to remove the contents from the pouch, a simple method of cutting one of the corners, for example with scissors, has sufficed for many end uses, in the home. However, with institutional purchasers such as restaurants, which purchase and use pouches containing relishes, mustard, chocolate sauces and the like, it is inconvenient to use scissors and also the snipped-off corner may contaminate the material after it has been poured or squeezed from the pouch.
Particularly for institutional purchasers, therefore, it is desirable that the pouch has a pouring spout, preferably one that can be resealed. It is known to incorporate pouring spouts into plastic pouches but this is expensive because of the need for one pouring spout per pouch. It would be economically more desirable if the spout was able to be inserted into the pouch and used until the pouch was empty, and then be removed and cleaned for re-use with another pouch.
One such pouring spout is disclosed in Canadian Patent 1 192 164 to L. Obidniak. In L. Obidniak's configuration, the pouring spout comprises an elongated body, one of the ends being pointed and the other being integrally prolonged by a threaded stem. A passage is provided for flow of liquid from the pouch. The disclosure of L. Obidniak indicates that the passage is preferably T-shaped. The T-shaped passage is ineffective for removing thick materials which include particulates therein, for example relish, from the pouch.
Another pouring spout, used for application to the side of a rigid paper carton, is disclosed in U.S. Pat. No. 2,598,843 to F. D. Sherwood, which issued 1952 Jun. 3.
A further pouring spout is disclosed in European Publication 0410 770 to R. P. Harrison and R. C. Wirsig, published 1991 Jan. 30. The disclosed spout comprises a tube having a piercing portion separated from a delivery portion by a film securement portion and having fluid flow communication from the piercing portion to the delivery portion. The film securement portion is adapted to secure, with a substantially liquid-tight seal, plastic film which has been pierced by the piercing portion. The piercing portion appears, in one perspective, to have been sliced at an angle to the longitudinal axis from a first location at one side of the tube adjacent the film securement portion to a second location at the other side of the tube, distal from the film securement portion, to form a tip. The tip appears, in a second perspective at 90.degree. to the first perspective, to have been sliced symmetrically about the longitudinal axis of the tube to from a pointed piercing tip furthest away from the film securement portion.
Particularly for institutional purchasers it is also useful that the pouches are contained in a dispenser for ease of handling. One such dispenser comprises i) a cylindrical container having sides and an open top having a rim, the container being adapted to contain the pouch, and ii) a lid attachable to the rim such that the lid is adapted to trap the ears of the pouch between the lid and the rim and to keep said end of the pouch taut between the ears when the lid is attached to the rim. The lid is also adapted to allow a spout to pierce the pouch at the taut portion. Such a dispenser and spouts therefor are disclosed in U.K. Patent Application 90.09846 filed 1990 May 2 to D. C. King and R. C. Wirsig.
When the piercing portions of the some of the spouts disclosed in European Patent Publication 0410 770 and U.K. Patent Application 90.09846 are worked into taut film there is a tendency for the piercing tip, after the initial point entry through the film, to "plough" its way into the film. The initial point entry is at or near the edge of the eventual opening in the film and the "ploughing" action is from the initial entry point, which is on one side of the eventual opening, over to the other side of the opening. This usually leads to film tearing at the edge of the film opening and thus may cause leakage of material from the pouch. With the nozzle in FIG. 9 of U.K. Patent Application 90.09846, puncturing and opening of the film depends on a die cutting action by the serrated edges to make the initial opening in the film. This initial opening is stretched only slightly before a seal is attempted. In the case of relatively non-stretchy films, which are typically also difficult to cut through, such nozzles tend to cause tearing of the film, thus making sealing difficult. Even if the cut-through is clean, i.e. no edge tearing, the amount of stretch given to the film is often insufficient to effect a good seal. The type of spout disclosed in the aforementioned Canadian Patent assists in overcoming the leakage problem just mentioned but suffers from the fact that the T-shaped passage does not allow "lumpy" materials to flow easily through the bore of the spout.
It is believed that the keys to obtaining a good seal around a tubular spout, when used with a relatively non-stretchy film are to insert the spout by making the initial puncture in the film small and in the center of the eventual opening, and then ploughing the opening evenly in all directions from the initial puncture. It is also believed that to so insert the spout, tearing of the film around the opening is minimized, thus making sealing easier.